The present invention relates to watercrafts and to propulsion systems for watercrafts, and more particularly to a watercraft propulsion system deriving its power from the waves.
Different proposals have been made for utilizing the energy in the waves to propel a watercraft such as a boat, a ship or the like. Some of these proposals have used the up-and-down motion caused by the waves to operate a compressor or a pump to pressurize a fluid which is used directly or indirectly to propel the watercraft. For example, in U.S. Pat. No. 3,002,384, Dube describes a boat in which pumps operated by pivoting arms connecting pontoons to the boat are used to provide supplemental pressurized fluid to drive the propellers in case the main engine fails. Normally, however, the pistons in the pumps are pressurized so that the pontoons are forced into the water to raise the boat into a planing orientation, and the pumps act as shock absorbers. A conventional fuel-consuming engine provides pressurized fluid which is normally used to drive the propellers, and the pumps powered by the pontoons provide auxilliary power in case of main engine failure. The propellers are driven directly by hydraulic motors, and the propulsion system for the boat does not include a transmission system.
In U.S. Pat. No. 1,172,737, Roach describes a ship which has a bow float, a stern float, and a number of side floats which are connected to the ship such that their up-and-down movements compress air in cylinders and directly drive the propellers through a gearing arrangement. The compressed air is stored in tanks to provide protection for the ship structure and is provided to air motors to drive the ship.
Devlan, in U.S. Pat. No. 154,324, provides a vessel with wells extending vertically therethrough and open at both ends. Floats within the wells rise and fall with the waves to compress air within cylinders, and the compressed air is used directly or indirectly for propulsion. The up and down motion of the floats is also used to drive gears connected to the ship's propellers. In U.S. Pat. No. 3,527,188, issued to Shepard et al., a ship is made of two sections joined by a hinged connection and interconnected with plunger-and-cylinder assemblies so that the front section moves up and down with the wave to pressurize a fluid used to drive a hydraulic motor which in turn drives an electric generator, and the electricity is used to operate an electric motor connected to the ship's propellers.
White, U.S. Pat. No. 1,532,459, describes a boat having a submerged plate which moves with the waves to operate a pump which pressurizes water used to drive a water turbine connected to a propeller. In the British patent to Hocevar, No. 94,962, the wave-powered propulsion system includes life boats which are pivotally connected to the ship by outrigger arms, with the pivotal motion of the outrigger arm used to drive a piston-cylinder arrangement through pulleys. The piston pressurizes a fluid used to drive a fluid motor connected to the ship's propellers. In addition to locating the floats at the sides of the ship, Hocevar also indicates that a float may be towed behind the ship which is also used to drive a hydraulic piston.
In another group of proposals, the motion of the wave is transferred directly to driving gears by means of a pivoted lever. For example, in the patent to Kalfas, U.S. Pat. No. 2,048,339, a float moves up and down with the waves to oscillate a lever connected to a gear train coupled to a propeller shaft, while in Kapolkin, U.S. Pat. No. 2,364,535, a boat built in two sections is joined by a pivot, with the pivotal motion of the front section oscillating a lever driving a transmission connected to a propeller. In Lamberti, U.S. Pat. No. 4,389,843, several float-and-pivoted-arm assemblies are connected by sprockets and chains to gear trains operating an electric generator which supplies current to a boat-propelling electric motor.
In the patent to Schulze, U.S. Pat. No. 1,033,476, barrels move with the waves and the pivotal motion of levers attached thereto is transmitted to drive gears by interconnecting chains. The gears may drive the propellers directly or may be used to drive an electric generator, with electricity being stored and used to drive an electric motor connected to the propeller. Reed, U.S. Pat. No. 2,556,340, uses a rocking pendulum weight to drive a hydraulic compressor which provides pressurized fluid to a hydraulic motor used to drive the propellers for a small boat.
While not specifically related to wave-powered propulsion systems, U.S. Pat. Nos. 4,210,821, 4,184,336, 3,664,125, 2,477,691 and 901,117 describe water-borne buoyant devices utilizing wave energy to produce electricity.
The proposals advanced thus far for utilizing the energy of waves to propel a watercraft, such as those mentioned above, have disadvantages, and none have enjoyed any degree of acceptance of which the applicant is aware.